The RTX 2080 Ti has a 450 MHz higher core clock speed and 160 more Texture Mapping Units than the HD 6870. This results in the RTX 2080 Ti providing 266.4 GTexel/s better texturing performance. This still holds weight but shader performance is generally more relevant, particularly since both of these GPUs support at least DirectX 10.

The RTX 2080 Ti has a 450 MHz higher core clock speed and 24 more Render Output Units than the HD 6870. This results in the RTX 2080 Ti providing 61.2 GPixel/s better pixeling performance. However, both GPUs support DirectX 9 or above, and pixeling performance is only really relevant when comparing older cards.

The RTX 2080 Ti was released over three years more recently than the HD 6870, and so the RTX 2080 Ti is likely to have far better driver support, meaning it will be much more optimized and ultimately superior to the HD 6870 when running the latest games.

Both GPUs exhibit very powerful performance, so it probably isn't worth upgrading from one to the other, as both are capable of running even the most demanding games at the highest settings.

The RTX 2080 Ti has 9216 MB more video memory than the HD 6870, so is likely to be much better at displaying game textures at higher resolutions. This is supported by the fact that the RTX 2080 Ti also has superior memory performance overall.

The RTX 2080 Ti has 347.2 GB/sec greater memory bandwidth than the HD 6870, which means that the memory performance of the RTX 2080 Ti is massively better than the HD 6870.

The GeForce RTX 2080 Ti SLI has 4352 Shader Processing Units and the Radeon HD 6870 Crossfire has 2240. However, the actual shader performance of the RTX 2080 Ti is 7116 and the actual shader performance of the HD 6870 is 1008. The RTX 2080 Ti having 6108 better shader performance and an altogether better performance when taking into account other relevant data means that the RTX 2080 Ti delivers a massively smoother and more efficient experience when processing graphical data than the HD 6870.

The RTX 2080 Ti transistor size technology is 28 nm (nanometers) smaller than the HD 6870. This means that the RTX 2080 Ti is expected to run slightly cooler and achieve higher clock frequencies than the HD 6870.

The GeForce RTX 2080 Ti SLI requires 260 Watts to run and the Radeon HD 6870 Crossfire requires 302 Watts. We would recommend a PSU with at least 650 Watts for the RTX 2080 Ti and a PSU with at least 600 Watts for the HD 6870. The HD 6870 requires 42 Watts more than the RTX 2080 Ti to run. The difference is significant enough that the HD 6870 may have a slight adverse affect on your yearly electricity bills in comparison to the RTX 2080 Ti.

GPU Supporting Hardware

Gaming Performance Value

Performance Value

GPU Mini Review

Mini Review

Overview
GeForce RTX 2080 Ti is the top RTX 20 Series graphics card and considered an Enthusiast graphics card based on the Turing architecture.
Architecture
The Turing architecture represents a process shrink down to 12nm compared to 14nm Pascal. The Turing architecture provides the world's first consumer support for real-time ray-tracing technology, or RTX.
GPU
It equips a GPU Codenamed TU102 which has 4352 Shader Processing Units, 272 TMUs and 88 ROPs. The central unit runs at 1350MHz and goes up to 1545MHz in Boost mode. It also has 544 Tensor Cores for AI purposes.
Memory
The GPU accesses an 11GB frame buffer of first-gen GDDR6 memory through a 352-bit memory interface, while the Memory clock operates at 1750MHz, or 14GHz effective.
Power Consumption
With a rated board TDP of 285W, it requires at least a 650W PSU with two 8-pin power connectors.
System Suggestions
GeForce RTX 2080 Ti is best suited for resolutions up to and including 3840x2160. We recommend a top-End Processor and at least 16GB of RAM for optimal performance.

Radeon HD 6870 Crossfire is a solution of two Radeon HD 6870 put together using AMD'S Crossfire technology.
Check the page of Radeon HD 6870 to know more about its chip.
Crossfire relies a lot on proper driver support and may suffer from micro-stuttering in lower frame rates (below 30). Benchmarks indicate the performance is overall, is up to 67% better than a single Radeon HD 6870 performing by itself but it might be worse (depending on whether or not the 3D game supports crossfire or in the graphics driver) than a single Radeon HD 6870. Expect this combination to draw up to 302 Watt though the average power consumption should be slightly lower.
Even the most demanding games will run at the highest settings.